Optimization of Infiltration and Drying Processes for Pre-Gelatinized Hulless Barley Rice: Effects on Quality, Texture, and Bioactive Compound Retention.

Hulless barley (Hordeum vulgare L. var. nudum) is a nutritious cereal but suffers from prolonged cooking and asynchronous gelatinization with rice. Pre-gelatinization technology can address these issues, yet optimal processing parameters are needed to preserve its bioactive components. This study optimized the infiltration and drying processes for pre-gelatinized hulless barley rice. Infiltration cycles and durations were evaluated using sensory scores, texture analysis, and gelatinization degree; drying temperatures (80-160 °C) and times were optimized based on quality and nutrient retention. Secondary infiltration for 4 h significantly outperformed traditional soaking, yielding higher retention of polyphenols (130.73 mg/100 g), flavonoids (50.01 mg/100 g), and β-glucan (2.96%). Drying at 80-100 °C for 90-120 min produced the best sensory and textural properties, maximal retention of polyphenols (128.46 mg/100 g), flavonoids (45 mg/100 g), β-glucan (3.1%), and reducing sugars (482.84 mg/100 g at 80 °C/120 min), and the highest DPPH and ABTS+ radical scavenging activities. Higher temperatures (≥120 °C) caused significant degradation of these functional components and reduced antioxidant capacity. The optimal combination-secondary infiltration for 4 h followed by drying at 80-100 °C for 90-120 min-effectively balances processing efficiency with nutritional and functional quality. This optimized process provides a practical technical solution for large-scale production of high-quality pre-gelatinized hulless barley rice.